1. Field of the Invention
This invention relates to a web server constituting a single sign-on system, a method of controlling the operation of this web server, and a non-transitory recording medium storing a program for controlling the operation of the web server.
2. Description of the Related Art
Authentication is often required when a user utilizes a server (see Japanese Patent Application Laid-Open No. 2009-247030). Since performing such authentication for every server is troublesome, use is made of a single sign-on system in which a user can utilize all allowed functions merely by being authenticated a single time (see Japanese Patent Application Laid-Open Nos. 2005-153261, 2009-501014 and 2002-288139).
However, since single sign-on allows utilization of multiple servers by a single authentication, there is a need for more robust authentication.